aoc1609_decompress.cpp

/* ************************************************************************** */
/*                                                                            */
/*                            \\             /`/``                            */
/*                            ~\o o_       0 0\                               */
/*                            / \__)      (u  ); _  _                         */
/*                     / \/ \/  /           \  \/ \/ \                        */
/*                    /(   . . )            (         )\                      */
/*                   /  \_____/              \_______/  \                     */
/*                       []  []               [[] [[]    *.                   */
/*                       []] []]              [[] [[]                         */
/*                                                                            */
/* ****************************************************************** nuo *** */


#include "iostream"
#include "sstream"
#include "vector"
#include "string"

long    decompress_omega(std::string s);
int     decompress_alpha(std::string s);

int     main()
{
        std::string s;
        long        len1;
        long        len2;        

        std::cin >> s;
        len1 = decompress_alpha(s);
        len2 = decompress_omega(s);
        
        std::cout << "Star 1 : " << len1 << std::endl;
        std::cout << "Star 2 : " << len2 << std::endl;
        return (0);
}

long    decompress_omega(std::string s)
{
        std::size_t L;
        std::size_t R;
        std::string sub;
        long        len;
        char        c;
        int         a;
        int         b;

        len = 0;
        L = 0;
        R = 0;
        if (s.find('(') == std::string::npos)
            return ((long) s.length());
        while (s.find('(') != std::string::npos)
        {
            L = s.find('(');
            R = s.find(')');
            if (R != std::string::npos)
            {
                std::stringstream ss(s.substr(L + 1, R - 1));
                ss >> a >> c >> b;
                //  debug
                //std::cout << a << ' ' << c << ' ' << b << std::endl;
                len += L;
                s = s.substr(R + 1);
                len += b * decompress_omega(s.substr(0, a));
                s = s.substr(a);
            }
        }
        return (len + (long) s.length());
}


int     decompress_alpha(std::string s)
{
        std::size_t L;
        std::size_t R;
        char        c;
        int         len;
        int         a;
        int         b;
        int         i;

        len = i = 0;
        while (s[i])
        {
            s = s.substr(i);
            L = s.find('(');
            if (L != std::string::npos)
            {
                R = s.find(')');
                if (R != std::string::npos)
                {
                    std::stringstream ss(s.substr(L + 1, R - 1));
                    ss >> a >> c >> b;
                    len += L + a * b;
                    i = R + a + 1;
                }
            }
            else
            {
                len += (int) s.length();
                break;
            }
        }
        return (len);
}